The proposed fix to the cross-state pollution rule would allow 10 states, especially Texas, to emit more smog-causing pollution than had initially been permitted. The rule is designed to decrease smokestack emissions, mostly from coal-fired power plants, in 27 states, that contribute to unhealthy air downwind.

Texas, faced with a growing population, few new energy sources, hot summers and more coal-fired power plants than any other state, has vocally opposed the rule.

Perry has used it as fodder in his long-standing accusation that the EPA under President Barack Obama meddles in state affairs and lays down expensive regulations in tough economic times, forcing companies to cut jobs to offset the costs of compliance. He wrote a letter to Obama last month urging him to delay implementation of the rule after one of the state's largest energy suppliers, Luminant Generation Co., announced it would have to idle two units and layoff hundreds of workers to comply with the rules by 2012.

Perry said the changes proposed by the EPA "prove there are undeniable flaws" with the rule and that he will "continue to fight the job killing mandates passed down by this administration and the unelected bureaucrats at the EPA."

But EPA regional administrator Al Armendariz said the agency's decision to ease the standards had to do with new data and was not political. He also noted no changes have been made to the compliance calendar Texas and other states had criticized. The changes will also ease the restrictions for Florida, Louisiana, Michigan, Mississippi, Nebraska, New Jersey, New York, Wisconsin and Arkansas.

The rule is meant to help reduce smokestack pollution causing smog and soot in downwind states. For example, forcing Texas to decrease emissions of sulfur dioxide and nitrogen oxide — smog and acid-rain causing pollutants — would help clean the air in Illinois, Michigan and Missouri, while cutting pollution from Louisiana, Arkansas, Oklahoma and Missouri would help residents in the Lone Star State.

Texas has challenged the rule in court, and Attorney General Greg Abbott said the state would continue to pursue its lawsuit.

The restrictions "threaten job losses for hard-working Texans, undermine electric reliability for Texas families and violate federal law — and minor technical corrections cannot make these regulations lawful," Abbott said in a statement. "By making the minor changes ... the Obama administration effectively concedes that its rules were flawed — but inexplicably refuses to resolve the real defects."

The rule gives more leeway to the dirtiest facilities, and the EPA says the data it initially used led it to believe some of Luminant's "scrubbers" — technology designed to decrease sulfur dioxide emissions — to be 95 percent effective. In recent weeks, in talks with Luminant, it became apparent those scrubbers were only about 70 percent effective.

"The technical adjustments that we're making to the cross-state rule are not the result of political pressures and are not the result of anything other than a better understanding of actual operations of utilities," Armendariz said.

When the EPA initially calculated the decrease for each area, it used information utility companies provide to the Energy Information Administration. The change will allow the 10 states to emit 76,000 tons more pollution — 70,000 tons from Texas. This is about 2 percent of the total pollution the EPA will regulate under the new rule.

Luminant spokesman Allan Koenig said the company was still reviewing the proposal to see whether it would prevent the idling of two units and the layoffs of hundreds of workers. Koenig noted the compliance calendar for 2012 remains the same.

"It is a step forward that the agency has now proposed changes, validating the rule issued in July 2011 has flaws in its provisions for Texas," Koenig said in a statement.

The Texas Commission on Environmental Quality also welcomed the revisions, calling the original rules "fatally flawed because of its effects on jobs and electric reliability."

House Republicans have put the EPA at the center of their anti-regulatory agenda, passing bills to halt or delay rules on greenhouse gases, and toxic air pollution from power plants and cement factories. Last week, they passed legislation that would scrap the cross-state pollution rule. The measures are unlikely to pass the Democratic-controlled Senate, and the White House has threatened to veto them.

Chairman of the House Science, Space and Technology Committee U.S. Rep. Ralph Hall, R-Texas, said the EPA's revisions prove the rules were not based on sound science.

"As we have seen in Texas and throughout the United States, pursing an EPA-knows-best approach to compliance will unquestionably result in increased unemployment, power plant shutdowns and more expensive, less reliable energy," Hall said.

Environmental groups warned against easing the regulations. Tom "Smitty" Smith, director of Public Citizen in Texas, said "dirty old plants will continue to emit lung searing acid gasses."

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Ramit Plushnick-Masti can be followed on Twitter at https://twitter.com/RamitMastiAP